Vol. 7, Issue 5 (2018)

Author(s):
David Kamei and Sobita Devi Simon

Abstract:
Emerging fungicides evaluation will help in determining efficacy against the target pathogens and avoid its indiscriminate use and economic losses. The use of bio-agents Pseudomonas fluorescent can effectively suppressed the pathogen through mycoparasitism, antibiosis and plant immunity through induce resistance and find best alternative to chemical use in sustainable crop pest management system. In our present studies 5 fungicides viz. Thiophanate, Myclobutanil, Carbendazim, Propineb, Propiconazole and bio-agent Pseudomonas fluorescent isolates were used against brown spot disease of rice caused by Helminthosporium oryzae (Breda de Haan). In-vitro studies in broth media revealed most significant effect on fungal biomass production was recorded in Propiconazole (0.05 g) followed by Propineb (0.07 g). On solid media minimum radial growth was recorded in Propiconazole (2.73 cm) followed by Propineb (2.86 cm) in compared with others including Control. The antagonistic effect of Pseudomonas fluorescent on dual culture test found most significant reduction on linear growth of Helminthosporium oryzae was found at P. fluorescent cell conc. of 1.3x10⁸/ml (4.29 cm) with percent inhibition 52.23 over the untreated Control. Pooled data of the two consecutive in-vivo trials revealed that all the fungicides and P. fluorescent significantly reduced incidence of H.oryzae in compared with untreated Control. Among the treatment significantly reduced the disease incidence was recorded in T₆ (7.39) followed by T₅ (7.91), T₂ (9.63), T₄ (9.97), T₃ (10.77), T₁ (16.00) from Control (27.12), whereas T₄-Pseudomonas fluorescent significantly reduced disease incidence from T₁ and T₃. However (T₄&T₂) are not significant on each other. Fungicides and bio-agent P.fluorescent were found to have a significant increase on plant parameters being investigated viz., plant high, flag leaf, number of filled grain and the overall grain yield parameter.